Letter: Letters : That's impossible

From George Lafferty

Poynton, Cheshire

Thanks to the article by Jack Cohen and Ian Stewart
(“That’s amazing, isn’t it?”, 17 January, p 24),
I will now desist from boring my friends with the
astounding fact that last year I bumped into my sister, quite by chance, in
Disneyland Paris, when neither of us knew that the other was going to be there.
Dinner parties will never be the same again.

Unfortunately, I will not be able to use the article as ammunition to stop my
bridge-playing friends making the utterly preposterous claim that they know
someone who knows someone who once had a “perfect deal” in a randomly dealt
hand.

It is not true that the number of games going on at any time, anywhere in the
world, is high enough for there to be a reasonable chance of this happening. The
probability is so small that it would require every single living person in the
world to play one million million deals before the chance of a perfect deal
occurring was even as large as your favourite set of numbers coming up in the
National Lottery.

The probability of any one player getting all 13 cards of a suit (with the
other cards shared randomly among the other three players) is much larger, at
about one in a hundred billion per deal. But even this probability is so tiny
that the chances of the event ever having happened in the history of bridge must
be very small indeed.

However, seemingly honest and reliable people do occasionally report perfect
deals. The explanation is simply that the deck was fixed when their backs were
turned, the dealer engaged in some sleight of hand, or the deck had not been
properly shuffled after the previous hand.